1. Technical Field
The present invention relates to processes for producing olefin-terminated polyesters. More particularly, the invention relates to a process for producing an olefin-terminated polyester which comprises reacting an olefin-terminated diester compound with a lactone compound and a process for producing an olefin-terminated polyester which comprises copolymerizing an olefin-terminated diester compound, a lactone compound, a cyclic acid anhydride and an epoxy compound.
2. Background Art
Aliphatic polyesters, thanks to their high flexibility and excellent resistance to heat, have heretofore been utilized as components of thermoplastic elastomers, urethane elastomers, adhesive systems, coating compositions, etc. or as plastizers or modifying agents for a variety of polymers.
The processes known to the art for the production of aliphatic polyesters include the polycondensation reaction of a diol compound with a dibasic acid or a derivative thereof, which yields a hydroxy- or carboxy-terminated polyester, and the polymerization reaction of a lactone compound using a hydroxy-containing initiator compound, for example a glycol, which yields a hydroxy-terminated polyester. However, hydroxy- or carboxy-terminated polyesters are limited in the scope of application and many attempts have heretofore been made to replace these terminal groups with other functional groups. Particularly, olefin-terminated polyesters are of immense use because of their diversity of reactivity.
In one of the hitherto-known production processes for olefin-terminated polyesters, the polycondensation reaction between a diol compound and a dibasic acid or a derivative thereof is conducted in the presence of an olefin-terminated monoalcohol or monocarboxylic acid or a reactive derivative thereof. In an alternative process, a hydroxy- or carboxy-terminated polyester is first produced and, then, the terminal OH or COOH group is modified. However, these processes are disadvantageous in that, inter alia, the reaction conditions must be critically controlled in order that the olefinic group may be introduced into the terminus of the polyester chain in a sufficiently high yield.
Polyesters terminated with a variety of functional groups can be synthesized by reacting ester compounds having the corresponding functional groups with .epsilon.-caprolactone as described, inter alia, in Japanese Kokai Patent Publication No. 61-37813 and this method may of course be utilized for the synthesis of olefin-terminated polyesters. However, this process is disadvantageous in that the homopolymerization reaction of .epsilon.-caprolactone is given priority to the insertion reaction of the lactone into the ester compound so that the olefinic terminal modification rate cannot be as high as desired. Stated differently, an olefin-terminated polyester containing many ester bonds, that is to say an olefin-terminated polyester containing many lactone chains cannot be obtained.